New Roots Development
Tool Guide
Home›Tool Guide›VDC Survey›GIS

Image Place (locate a screen clip by point pairs)

Half a day of hand tracing, assisted: you click, the line finds the edge; one click outlines a roof or a pond. Concept-plan accuracy from county, state, NAIP or your own drone imagery. Plain AutoCAD.

Command VDCIMAGETRACE VDCIMAGEPLACE · VDC Survey tab › GIS panel

VDCIMAGEPLACE is part of Image Trace (assisted trace of aerial imagery); the full section follows.

Half a day of hand tracing, assisted: you click, the line finds the edge; one click outlines a roof or a pond. Concept-plan accuracy from county, state, NAIP or your own drone imagery. Plain AutoCAD.
Edge-snap: click, click, the line follows the edge  |  Region grow: one click, one outline straight line it did NOT take Edge-snap trace Least-cost path through the image gradient, inside a corridor around your clicks. U backs up, C closes, Enter writes. Region grow Flood by color, fill holes, trace the outline, simplify, square the building corners. Tighter / Looser re-run a leaky click. Image Place 2-3 point pairs: scale + rotate + move a clip. Never trace Google / Bing. Warns on the online map.
Traced polyline   Your clicks   What a plain straight line would do

What it does

  • Feature presets set the layer (V-ROAD-EDGE-TRCE, V-BLDG-TRCE, V-VEGE-TREE-TRCE, V-HYDR-WATR-TRCE, V-ROAD-DRIV-TRCE, V-WALK-TRCE), closed or open, squared or not.
  • Pixels from the attached image's file (full resolution, through its placement) or a snapshot of the plan view (anything on screen).
  • Edge-snap: clicks snap onto a nearby edge; the span between clicks follows the edge; live preview; straight segments reported with the reason.
  • Region grow: outline of the clicked area, holes filled, simplified, squared for buildings; written at once, Undo / Tighter / Looser.
  • Image Place: similarity fit from 2 or 3 point pairs; misfit reported.

Watch for

  • Licence: county, state, NAIP, own drone imagery supported; Google / Bing never; Esri online map = warned.
  • Concept-plan accuracy - a pixel or two of the image, and only as good as its placement.
  • Screen source needs the Model tab and a plan view. MrSID / ECW / JPEG 2000 files: export a PNG / TIF or use the screen.
  • Settings %APPDATA%\VDC\ImageTrace\settings.json.

Dialog

Image Trace (assisted trace of aerial imagery) dialog
Image Trace (assisted trace of aerial imagery) - VDCIMAGETRACE
Image Place (locate a screen clip by point pairs) dialog
Image Place (locate a screen clip by point pairs) - VDCIMAGEPLACE
Image Place (locate a screen clip by point pairs) dialog
Image Place (locate a screen clip by point pairs) - VDCIMAGEPLACE

Dialog

Image Trace (assisted trace of aerial imagery) dialog
Image Trace (assisted trace of aerial imagery) - VDCIMAGETRACE
Image Place (locate a screen clip by point pairs) dialog
Image Place (locate a screen clip by point pairs) - VDCIMAGEPLACE
Image Place (locate a screen clip by point pairs) dialog
Image Place (locate a screen clip by point pairs) - VDCIMAGEPLACE

When to use it

  • A concept plan needs edge of pavement, driveways, sidewalks and tree lines the county does not publish.
  • Buildings or ponds that are missing from the county footprints.
  • After Site Data's Existing conditions pull, to fill the gaps it reports.

How to run it

  1. Attach the county ortho / NAIP / drone image (or zoom the plan view onto it).
  2. Run VDCIMAGETRACE - pick the mode, the feature (sets the layer) and the pixel source.
  3. Edge-snap: click along the edge; U backs up, C closes, Enter writes the line.
  4. Region grow: click inside each roof or pond; Tighter / Looser re-run a click that leaked or fell short.
  5. Read the summary: what was written, any straight segments and why, the pixel size of each source.

Options

  • Pixel source: the attached image's file (full resolution) or a snapshot of the plan view (screen resolution, anything on screen).
  • Corridor / snap: how far from your clicks the line may wander, and how far a click moves onto an edge.
  • Color tolerance: how different a pixel may be from the clicked color and still join the region.
  • Square the corners: buildings come out with right-angle corners; true diagonals and bays are kept.

Watch out for

  • Never trace Google or Bing imagery, or screen clips of it - their terms ban it. The tool warns when the online map is on.
  • Accuracy is a pixel or two of the image at best, and only as good as the image's placement.
  • Shadows and tree canopy hide edges - click more often there, or draw that stretch straight.
  • MrSID / ECW / JPEG 2000 files cannot be read - export a PNG / JPG / TIF, or use the screen source.

Related: Image Place · Site Data · Site Snapshot